Hi @gbalciunas and very nice project you have there!
Let me tag our FEA expert @ggiraldo here who might give you some quick tips on how to improve your simulation. I am pretty sure he has covered this in the past (trying to find the related post and will paste it here).
P.S.: I think that should be the post where the user had a similar question: Bonded contact is a good approach to avoid simulating bolts?
Best,
Jousef